Various types of imaging devices are known in the art. Presently, one of the more popular types of imaging devices is that known as the electrophotographic imaging device which is commonly called a xe2x80x9claser printer.xe2x80x9d The fundamental operation of the electrophotographic imaging device is well understood in the art and includes providing a photoconductive surface often in the form of a rotatable drum. A laser, or other suitable light source, is selectively pulsed as it is directed at the moving photoconductive surface.
The selective pulsing of the light source as it is directed at the photoconductive surface causes the formation of the desired image on the surface in a latent, electrostatic form. A dry, powdered ink substance, known as xe2x80x9ctoner,xe2x80x9d is then applied to the photoconductive surface to xe2x80x9cdevelopxe2x80x9d the image, wherein the toner adheres essentially only to the latent image on the surface. The developed image, in the form of toner, is ultimately transferred from the photoconductive surface to a carrier media, such as a sheet of paper, and is affixed thereto.
Most conventional electrophotographic imaging devices include one or more reservoirs for containing a supply of the powdered toner. Generally, the toner reservoir is in the form of an enclosed hopper-like container having an opening through which the toner is dispensed during operation of the respective imaging device. In many cases, the toner reservoir is incorporated into a xe2x80x9ctoner cartridgexe2x80x9d which contains a given quantity of toner. The toner cartridge is designed to be conveniently removed from the imaging device when the toner is depleted. A like cartridge having a full supply of toner can then be replaced into the imaging device. As can be appreciated, the xe2x80x9creplaceable toner cartridgexe2x80x9d concept facilitates efficient operation of the imaging device by reducing down time due to toner depletion.
Many conventional toner cartridge configurations employ a temporary sealing device referred to as a xe2x80x9ctoner dam.xe2x80x9d The general purpose of the toner dam is to prevent toner from coming out of a full toner cartridge before the cartridge is installed into the imaging device. For example, without a toner dam, toner could inadvertently come out of a full toner cartridge during handling and shipment thereof, with undesirable results. The toner dam is generally installed during manufacture, or remanufacture, of the toner cartridge. Toner dams are described in greater detail in U.S. Pat. No. 5,799,712 to Kelly et al.
User instructions are usually provided on the toner cartridge packaging, and/or by other convenient means, which explain to the end-user how and why the toner dam should be removed from the cartridge prior to installation of the cartridge into an imaging device. However, as is the case with regard to nearly any product, the installation instructions go unheeded in a significant number of instances. The primary result of failing to remove the toner dam upon installation of the toner cartridge is, of course, that the imaging device will not function properly, if at all.
As can be expected, a secondary result of failing to remove the toner dam is that the end-user becomes frustrated due to the failure of the imaging device to function properly. This, in turn, often results in the end-user calling the manufacturer of the device, and/or the sales agent, to report an apparent malfunction of the imaging device. The manufacturer, and/or the sales agent, thus oftentimes incurs unnecessary expenses in connection with resolving the issue of the alleged xe2x80x9cmalfunctioningxe2x80x9d device.
Furthermore, as is discussed in U.S. Pat. No. 5,799,712, empty toner cartridges are often recycled by refilling them with toner at specially equipped facilities. However, the reinsertion of a toner dam into a previously used toner cartridge can be a relatively significant undertaking, accounting for a correspondingly significant proportion of the cost of recycling a given toner cartridge.
Additionally, problems are associated with the transport or movement of imaging devices with toner cartridges installed. More specifically, the transport or movement of an imaging device having a toner cartridge installed therein with the toner dam removed therefrom can generally result in damage to the device due to toner coming out of the cartridge. Therefore, it can be desirable to provide a toner cartridge having a sealing device which can alleviate the problems associated with the conventional toner dam as explained above.
More generally, various sealing devices are known in the art. For example, U.S. Pat. No. 3,984,942 to Schroth discloses an inflatable seal which can be employed to seal vehicle doors and the like. Such seals generally include a pliable inflatable member that can be filled with pressurized fluid, thereby causing expansion of the inflatable member. The expansion of the inflatable member, in turn, creates a sealing effect when the inflatable member is disposed between a door and a perimeterical doorframe, for example.
Similar inflatable members have been employed in various production devices and the like as is disclosed by U.S. Pat. No. 4,354,452 to Patterson. More specifically, Patterson discloses an edge dam which includes an inflatable member, wherein the edge dam is employed in an applicator for applying a coating liquid to a moving web of paper carried on a backing roll. While such inflatable members are known to function satisfactorily, such inflatable members are not generally well suited for providing a seal in place of the toner dam in toner cartridges.
This is because such inflatable members generally require a volume of working fluid such as air or hydraulic oil, as well as a pressurization/conveyance system for pressurizing the working fluid and conveying the fluid to and from the inflatable member. Such systems are thus generally too complex and too large for the application at hand.
In accordance with one embodiment of the present invention, an apparatus includes an object that defines an opening through which a material can selectively flow. The apparatus also includes a thermally activated sealing member that is configured to selectively change shape by way of heat activation, wherein sealing member can move between a first position in which the opening is substantially blocked so as to prevent material flow therethrough, and a second position in which the opening is substantially unblocked so as to enable material flow therethrough.